Spin-dependent electron scattering from optically active molecules

Abstract

The origin of the isomeric purity of biomolecules has been extensively discussed¹. In particular, it has been suggested that spin-polarized electrons or positrons emerging in the β-decay of radio-active nuclei may have led to a preferential destruction of one of the two isomers at an early stage of evolution and that this process tipped the initial balance of abundance of the two self-replicating isomers². As experimental tests of this hypothesis have remained largely inconclusive^3,4, it seemed useful to investigate the spin dependence of electron scattering from optically active molecules under the simplest possible conditions. Here we describe an experiment which indicates that spin-polarized electrons, like polarized light, when scattered from optically active molecules, can ‘distinguish’ between right-handed and left-handed isomers.